Traditional metal aircraft wings comprise a segmented box structure (wingbox) formed from C-beams (spars), ribs, and stiffened skin panels (covers). Further fixed structures are provided beyond the leading and trailing edges of the wingbox to create an aerodynamic profile and to support moveable lift devices such as slats (leading edge) and flaps (trailing edge). Composite wings are generally structured in a similar manner, with spars, ribs and leading and trailing edge fixed structures. Such use of composite materials in metallic-derived architectures is often known as “black aluminium” design.
FIG. 1 is an internal view of a section 1 of a composite wing structured according to the “black aluminium” design approach. The wing section 1 comprises a wingbox formed by a front spar 2, a rear spar 3, an upper cover panel 4, and a lower cover panel 5. A fixed leading edge structure 6 is fixedly attached to the front spar 2 and to the front cover overhangs (i.e. the parts of the upper cover panel 4 and the lower cover panel 5 which extend forward of the front spar 2). The fixed leading edge structure houses structure and mechanisms associated with leading edge high-lift devices, but it is not itself intended to carry any of the spanwise primary loads (e.g. wing bending loads) experienced during operation of the wing section on an aircraft. Instead, substantially all of the primary loads are transmitted to the wingbox via the fixed attachment to the front spar 2. A similar trailing edge structure (not shown) will typically be attached to the rear spar 3. The locations of fasteners are indicated by black dots. The spars 2, 3 and cover panels 4, 5 comprise portions of composite material. It will be appreciated from FIG. 1 that a significant number of fasteners must be provided through the composite material of the spars and cover panels to form the wingbox.